/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET  is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              Definitions for the Forwarding Information Base.
 *
 * Authors:     A.N.Kuznetsov, <kuznet@ms2.inr.ac.ru>
 */

#ifndef _NET_IP_FIB_H
#define _NET_IP_FIB_H

#include <net/flow.h>
#include <linux/seq_file.h>
#include <linux/rcupdate.h>
#include <net/fib_notifier.h>
#include <net/fib_rules.h>
#include <net/inet_dscp.h>
#include <net/inetpeer.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/refcount.h>
#include <linux/ip.h>
#include <linux/in_route.h>

struct fib_config {
        u8                      fc_dst_len;
        dscp_t                  fc_dscp;
        u8                      fc_protocol;
        u8                      fc_scope;
        u8                      fc_type;
        u8                      fc_gw_family;
        /* 2 bytes unused */
        u32                     fc_table;
        __be32                  fc_dst;
        union {
                __be32          fc_gw4;
                struct in6_addr fc_gw6;
        };
        int                     fc_oif;
        u32                     fc_flags;
        u32                     fc_priority;
        __be32                  fc_prefsrc;
        u32                     fc_nh_id;
        struct nlattr           *fc_mx;
        struct rtnexthop        *fc_mp;
        int                     fc_mx_len;
        int                     fc_mp_len;
        u32                     fc_flow;
        u32                     fc_nlflags;
        struct nl_info          fc_nlinfo;
        struct nlattr           *fc_encap;
        u16                     fc_encap_type;
};

struct fib_info;
struct rtable;

struct fib_nh_exception {
        struct fib_nh_exception __rcu   *fnhe_next;
        int                             fnhe_genid;
        __be32                          fnhe_daddr;
        u32                             fnhe_pmtu;
        bool                            fnhe_mtu_locked;
        __be32                          fnhe_gw;
        unsigned long                   fnhe_expires;
        struct rtable __rcu             *fnhe_rth_input;
        struct rtable __rcu             *fnhe_rth_output;
        unsigned long                   fnhe_stamp;
        struct rcu_head                 rcu;
};

struct fnhe_hash_bucket {
        struct fib_nh_exception __rcu   *chain;
};

#define FNHE_HASH_SHIFT         11
#define FNHE_HASH_SIZE          (1 << FNHE_HASH_SHIFT)
#define FNHE_RECLAIM_DEPTH      5

struct fib_nh_common {
        struct net_device       *nhc_dev;
        netdevice_tracker       nhc_dev_tracker;
        int                     nhc_oif;
        unsigned char           nhc_scope;
        u8                      nhc_family;
        u8                      nhc_gw_family;
        unsigned char           nhc_flags;
        struct lwtunnel_state   *nhc_lwtstate;

        union {
                __be32          ipv4;
                struct in6_addr ipv6;
        } nhc_gw;

        int                     nhc_weight;
        atomic_t                nhc_upper_bound;

        /* v4 specific, but allows fib6_nh with v4 routes */
        struct rtable __rcu * __percpu *nhc_pcpu_rth_output;
        struct rtable __rcu     *nhc_rth_input;
        struct fnhe_hash_bucket __rcu *nhc_exceptions;
};

struct fib_nh {
        struct fib_nh_common    nh_common;
        struct hlist_node       nh_hash;
        struct fib_info         *nh_parent;
#ifdef CONFIG_IP_ROUTE_CLASSID
        __u32                   nh_tclassid;
#endif
        __be32                  nh_saddr;
        int                     nh_saddr_genid;
#define fib_nh_family           nh_common.nhc_family
#define fib_nh_dev              nh_common.nhc_dev
#define fib_nh_dev_tracker      nh_common.nhc_dev_tracker
#define fib_nh_oif              nh_common.nhc_oif
#define fib_nh_flags            nh_common.nhc_flags
#define fib_nh_lws              nh_common.nhc_lwtstate
#define fib_nh_scope            nh_common.nhc_scope
#define fib_nh_gw_family        nh_common.nhc_gw_family
#define fib_nh_gw4              nh_common.nhc_gw.ipv4
#define fib_nh_gw6              nh_common.nhc_gw.ipv6
#define fib_nh_weight           nh_common.nhc_weight
#define fib_nh_upper_bound      nh_common.nhc_upper_bound
};

/*
 * This structure contains data shared by many of routes.
 */

struct nexthop;

struct fib_info {
        struct hlist_node       fib_hash;
        struct hlist_node       fib_lhash;
        struct list_head        nh_list;
        struct net              *fib_net;
        refcount_t              fib_treeref;
        refcount_t              fib_clntref;
        unsigned int            fib_flags;
        unsigned char           fib_dead;
        unsigned char           fib_protocol;
        unsigned char           fib_scope;
        unsigned char           fib_type;
        __be32                  fib_prefsrc;
        u32                     fib_tb_id;
        u32                     fib_priority;
        struct dst_metrics      *fib_metrics;
#define fib_mtu fib_metrics->metrics[RTAX_MTU-1]
#define fib_window fib_metrics->metrics[RTAX_WINDOW-1]
#define fib_rtt fib_metrics->metrics[RTAX_RTT-1]
#define fib_advmss fib_metrics->metrics[RTAX_ADVMSS-1]
        int                     fib_nhs;
        bool                    fib_nh_is_v6;
        bool                    nh_updated;
        bool                    pfsrc_removed;
        struct nexthop          *nh;
        struct rcu_head         rcu;
        struct fib_nh           fib_nh[] __counted_by(fib_nhs);
};

int __net_init fib4_semantics_init(struct net *net);
void __net_exit fib4_semantics_exit(struct net *net);

#ifdef CONFIG_IP_MULTIPLE_TABLES
struct fib_rule;
#endif

struct fib_table;
struct fib_result {
        __be32                  prefix;
        unsigned char           prefixlen;
        unsigned char           nh_sel;
        unsigned char           type;
        unsigned char           scope;
        u32                     tclassid;
        dscp_t                  dscp;
        struct fib_nh_common    *nhc;
        struct fib_info         *fi;
        struct fib_table        *table;
        struct hlist_head       *fa_head;
};

struct fib_result_nl {
        __be32          fl_addr;   /* To be looked up*/
        u32             fl_mark;
        unsigned char   fl_tos;
        unsigned char   fl_scope;
        unsigned char   tb_id_in;

        unsigned char   tb_id;      /* Results */
        unsigned char   prefixlen;
        unsigned char   nh_sel;
        unsigned char   type;
        unsigned char   scope;
        int             err;
};

#ifdef CONFIG_IP_MULTIPLE_TABLES
#define FIB_TABLE_HASHSZ 256
#else
#define FIB_TABLE_HASHSZ 2
#endif

__be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
                                 unsigned char scope);
__be32 fib_result_prefsrc(struct net *net, struct fib_result *res);

#define FIB_RES_NHC(res)                ((res).nhc)
#define FIB_RES_DEV(res)        (FIB_RES_NHC(res)->nhc_dev)
#define FIB_RES_OIF(res)        (FIB_RES_NHC(res)->nhc_oif)

struct fib_rt_info {
        struct fib_info         *fi;
        u32                     tb_id;
        __be32                  dst;
        int                     dst_len;
        dscp_t                  dscp;
        u8                      type;
        u8                      offload:1,
                                trap:1,
                                offload_failed:1,
                                unused:5;
};

struct fib_entry_notifier_info {
        struct fib_notifier_info info; /* must be first */
        u32 dst;
        int dst_len;
        struct fib_info *fi;
        dscp_t dscp;
        u8 type;
        u32 tb_id;
};

struct fib_nh_notifier_info {
        struct fib_notifier_info info; /* must be first */
        struct fib_nh *fib_nh;
};

int call_fib4_notifier(struct notifier_block *nb,
                       enum fib_event_type event_type,
                       struct fib_notifier_info *info);
int call_fib4_notifiers(struct net *net, enum fib_event_type event_type,
                        struct fib_notifier_info *info);

int __net_init fib4_notifier_init(struct net *net);
void __net_exit fib4_notifier_exit(struct net *net);

void fib_info_notify_update(struct net *net, struct nl_info *info);
int fib_notify(struct net *net, struct notifier_block *nb,
               struct netlink_ext_ack *extack);

struct fib_table {
        struct hlist_node       tb_hlist;
        u32                     tb_id;
        int                     tb_num_default;
        struct rcu_head         rcu;
        unsigned long           *tb_data;
        unsigned long           __data[];
};

struct fib_dump_filter {
        u32                     table_id;
        /* filter_set is an optimization that an entry is set */
        bool                    filter_set;
        bool                    dump_routes;
        bool                    dump_exceptions;
        bool                    rtnl_held;
        unsigned char           protocol;
        unsigned char           rt_type;
        unsigned int            flags;
        struct net_device       *dev;
};

int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
                     struct fib_result *res, int fib_flags);
int fib_table_insert(struct net *, struct fib_table *, struct fib_config *,
                     struct netlink_ext_ack *extack);
int fib_table_delete(struct net *, struct fib_table *, struct fib_config *,
                     struct netlink_ext_ack *extack);
int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
                   struct netlink_callback *cb, struct fib_dump_filter *filter);
int fib_table_flush(struct net *net, struct fib_table *table, bool flush_all);
struct fib_table *fib_trie_unmerge(struct fib_table *main_tb);
void fib_table_flush_external(struct fib_table *table);
void fib_free_table(struct fib_table *tb);

#ifndef CONFIG_IP_MULTIPLE_TABLES

#define TABLE_LOCAL_INDEX       (RT_TABLE_LOCAL & (FIB_TABLE_HASHSZ - 1))
#define TABLE_MAIN_INDEX        (RT_TABLE_MAIN  & (FIB_TABLE_HASHSZ - 1))

static inline struct fib_table *fib_get_table(struct net *net, u32 id)
{
        struct hlist_node *tb_hlist;
        struct hlist_head *ptr;

        ptr = id == RT_TABLE_LOCAL ?
                &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX] :
                &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX];

        tb_hlist = rcu_dereference_rtnl(hlist_first_rcu(ptr));

        return hlist_entry(tb_hlist, struct fib_table, tb_hlist);
}

static inline struct fib_table *fib_new_table(struct net *net, u32 id)
{
        return fib_get_table(net, id);
}

static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
                             struct fib_result *res, unsigned int flags)
{
        struct fib_table *tb;
        int err = -ENETUNREACH;

        rcu_read_lock();

        tb = fib_get_table(net, RT_TABLE_MAIN);
        if (tb)
                err = fib_table_lookup(tb, flp, res, flags | FIB_LOOKUP_NOREF);

        if (err == -EAGAIN)
                err = -ENETUNREACH;

        rcu_read_unlock();

        return err;
}

static inline bool fib4_has_custom_rules(const struct net *net)
{
        return false;
}

static inline bool fib4_rule_default(const struct fib_rule *rule)
{
        return true;
}

static inline int fib4_rules_dump(struct net *net, struct notifier_block *nb,
                                  struct netlink_ext_ack *extack)
{
        return 0;
}

static inline unsigned int fib4_rules_seq_read(const struct net *net)
{
        return 0;
}

static inline bool fib4_rules_early_flow_dissect(struct net *net,
                                                 struct sk_buff *skb,
                                                 struct flowi4 *fl4,
                                                 struct flow_keys *flkeys)
{
        return false;
}
#else /* CONFIG_IP_MULTIPLE_TABLES */
int __net_init fib4_rules_init(struct net *net);
void __net_exit fib4_rules_exit(struct net *net);

struct fib_table *fib_new_table(struct net *net, u32 id);
struct fib_table *fib_get_table(struct net *net, u32 id);

int __fib_lookup(struct net *net, struct flowi4 *flp,
                 struct fib_result *res, unsigned int flags);

static inline int fib_lookup(struct net *net, struct flowi4 *flp,
                             struct fib_result *res, unsigned int flags)
{
        struct fib_table *tb;
        int err = -ENETUNREACH;

        flags |= FIB_LOOKUP_NOREF;
        if (net->ipv4.fib_has_custom_rules)
                return __fib_lookup(net, flp, res, flags);

        rcu_read_lock();

        res->tclassid = 0;

        tb = rcu_dereference_rtnl(net->ipv4.fib_main);
        if (tb)
                err = fib_table_lookup(tb, flp, res, flags);

        if (!err)
                goto out;

        tb = rcu_dereference_rtnl(net->ipv4.fib_default);
        if (tb)
                err = fib_table_lookup(tb, flp, res, flags);

out:
        if (err == -EAGAIN)
                err = -ENETUNREACH;

        rcu_read_unlock();

        return err;
}

static inline bool fib4_has_custom_rules(const struct net *net)
{
        return net->ipv4.fib_has_custom_rules;
}

bool fib4_rule_default(const struct fib_rule *rule);
int fib4_rules_dump(struct net *net, struct notifier_block *nb,
                    struct netlink_ext_ack *extack);
unsigned int fib4_rules_seq_read(const struct net *net);

static inline bool fib4_rules_early_flow_dissect(struct net *net,
                                                 struct sk_buff *skb,
                                                 struct flowi4 *fl4,
                                                 struct flow_keys *flkeys)
{
        unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;

        if (!net->ipv4.fib_rules_require_fldissect)
                return false;

        memset(flkeys, 0, sizeof(*flkeys));
        __skb_flow_dissect(net, skb, &flow_keys_dissector,
                           flkeys, NULL, 0, 0, 0, flag);

        fl4->fl4_sport = flkeys->ports.src;
        fl4->fl4_dport = flkeys->ports.dst;
        fl4->flowi4_proto = flkeys->basic.ip_proto;

        return true;
}

#endif /* CONFIG_IP_MULTIPLE_TABLES */

static inline bool fib_dscp_masked_match(dscp_t dscp, const struct flowi4 *fl4)
{
        return dscp == (fl4->flowi4_dscp & INET_DSCP_LEGACY_TOS_MASK);
}

/* Exported by fib_frontend.c */
extern const struct nla_policy rtm_ipv4_policy[];
void ip_fib_init(void);
int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
                    struct netlink_ext_ack *extack);
__be32 fib_compute_spec_dst(struct sk_buff *skb);
bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev);
int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
                        dscp_t dscp, int oif, struct net_device *dev,
                        struct in_device *idev, u32 *itag);

static inline enum skb_drop_reason
fib_validate_source_reason(struct sk_buff *skb, __be32 src, __be32 dst,
                           dscp_t dscp, int oif, struct net_device *dev,
                           struct in_device *idev, u32 *itag)
{
        int err = fib_validate_source(skb, src, dst, dscp, oif, dev, idev,
                                      itag);
        if (err < 0)
                return -err;
        return SKB_NOT_DROPPED_YET;
}

#ifdef CONFIG_IP_ROUTE_CLASSID
static inline int fib_num_tclassid_users(struct net *net)
{
        return atomic_read(&net->ipv4.fib_num_tclassid_users);
}
#else
static inline int fib_num_tclassid_users(struct net *net)
{
        return 0;
}
#endif
int fib_unmerge(struct net *net);

static inline bool nhc_l3mdev_matches_dev(const struct fib_nh_common *nhc,
const struct net_device *dev)
{
        if (nhc->nhc_dev == dev ||
            l3mdev_master_ifindex_rcu(nhc->nhc_dev) == dev->ifindex)
                return true;

        return false;
}

/* Exported by fib_semantics.c */
int ip_fib_check_default(__be32 gw, struct net_device *dev);
int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force);
int fib_sync_down_addr(struct net_device *dev, __be32 local);
int fib_sync_up(struct net_device *dev, unsigned char nh_flags);
void fib_sync_mtu(struct net_device *dev, u32 orig_mtu);
void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig);

/* Fields used for sysctl_fib_multipath_hash_fields.
 * Common to IPv4 and IPv6.
 *
 * Add new fields at the end. This is user API.
 */
#define FIB_MULTIPATH_HASH_FIELD_SRC_IP                 BIT(0)
#define FIB_MULTIPATH_HASH_FIELD_DST_IP                 BIT(1)
#define FIB_MULTIPATH_HASH_FIELD_IP_PROTO               BIT(2)
#define FIB_MULTIPATH_HASH_FIELD_FLOWLABEL              BIT(3)
#define FIB_MULTIPATH_HASH_FIELD_SRC_PORT               BIT(4)
#define FIB_MULTIPATH_HASH_FIELD_DST_PORT               BIT(5)
#define FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP           BIT(6)
#define FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP           BIT(7)
#define FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO         BIT(8)
#define FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL        BIT(9)
#define FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT         BIT(10)
#define FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT         BIT(11)

#define FIB_MULTIPATH_HASH_FIELD_OUTER_MASK             \
        (FIB_MULTIPATH_HASH_FIELD_SRC_IP |              \
         FIB_MULTIPATH_HASH_FIELD_DST_IP |              \
         FIB_MULTIPATH_HASH_FIELD_IP_PROTO |            \
         FIB_MULTIPATH_HASH_FIELD_FLOWLABEL |           \
         FIB_MULTIPATH_HASH_FIELD_SRC_PORT |            \
         FIB_MULTIPATH_HASH_FIELD_DST_PORT)

#define FIB_MULTIPATH_HASH_FIELD_INNER_MASK             \
        (FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP |        \
         FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP |        \
         FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO |      \
         FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL |     \
         FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT |      \
         FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)

#define FIB_MULTIPATH_HASH_FIELD_ALL_MASK               \
        (FIB_MULTIPATH_HASH_FIELD_OUTER_MASK |          \
         FIB_MULTIPATH_HASH_FIELD_INNER_MASK)

#define FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK           \
        (FIB_MULTIPATH_HASH_FIELD_SRC_IP |              \
         FIB_MULTIPATH_HASH_FIELD_DST_IP |              \
         FIB_MULTIPATH_HASH_FIELD_IP_PROTO)

#ifdef CONFIG_IP_ROUTE_MULTIPATH
int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
                       const struct sk_buff *skb, struct flow_keys *flkeys);

static void
fib_multipath_hash_construct_key(siphash_key_t *key, u32 mp_seed)
{
        u64 mp_seed_64 = mp_seed;

        key->key[0] = (mp_seed_64 << 32) | mp_seed_64;
        key->key[1] = key->key[0];
}

static inline u32 fib_multipath_hash_from_keys(const struct net *net,
                                               struct flow_keys *keys)
{
        siphash_aligned_key_t hash_key;
        u32 mp_seed;

        mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed.mp_seed);
        fib_multipath_hash_construct_key(&hash_key, mp_seed);

        return flow_hash_from_keys_seed(keys, &hash_key);
}
#else
static inline u32 fib_multipath_hash_from_keys(const struct net *net,
                                               struct flow_keys *keys)
{
        return flow_hash_from_keys(keys);
}
#endif

int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
                 struct netlink_ext_ack *extack);
void fib_select_multipath(struct fib_result *res, int hash,
                          const struct flowi4 *fl4);
void fib_select_path(struct net *net, struct fib_result *res,
                     struct flowi4 *fl4, const struct sk_buff *skb);

int fib_nh_init(struct net *net, struct fib_nh *fib_nh,
                struct fib_config *cfg, int nh_weight,
                struct netlink_ext_ack *extack);
void fib_nh_release(struct net *net, struct fib_nh *fib_nh);
int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
                       struct nlattr *fc_encap, u16 fc_encap_type,
                       void *cfg, gfp_t gfp_flags,
                       struct netlink_ext_ack *extack);
void fib_nh_common_release(struct fib_nh_common *nhc);

/* Exported by fib_trie.c */
void fib_alias_hw_flags_set(struct net *net, const struct fib_rt_info *fri);
void fib_trie_init(void);
struct fib_table *fib_trie_table(u32 id, struct fib_table *alias);
bool fib_lookup_good_nhc(const struct fib_nh_common *nhc, int fib_flags,
                         const struct flowi4 *flp);

static inline void fib_combine_itag(u32 *itag, const struct fib_result *res)
{
#ifdef CONFIG_IP_ROUTE_CLASSID
        struct fib_nh_common *nhc = res->nhc;
#ifdef CONFIG_IP_MULTIPLE_TABLES
        u32 rtag;
#endif
        if (nhc->nhc_family == AF_INET) {
                struct fib_nh *nh;

                nh = container_of(nhc, struct fib_nh, nh_common);
                *itag = nh->nh_tclassid << 16;
        } else {
                *itag = 0;
        }

#ifdef CONFIG_IP_MULTIPLE_TABLES
        rtag = res->tclassid;
        if (*itag == 0)
                *itag = (rtag<<16);
        *itag |= (rtag>>16);
#endif
#endif
}

void fib_flush(struct net *net);
void free_fib_info(struct fib_info *fi);

static inline void fib_info_hold(struct fib_info *fi)
{
        refcount_inc(&fi->fib_clntref);
}

static inline void fib_info_put(struct fib_info *fi)
{
        if (refcount_dec_and_test(&fi->fib_clntref))
                free_fib_info(fi);
}

#ifdef CONFIG_PROC_FS
int __net_init fib_proc_init(struct net *net);
void __net_exit fib_proc_exit(struct net *net);
#else
static inline int fib_proc_init(struct net *net)
{
        return 0;
}
static inline void fib_proc_exit(struct net *net)
{
}
#endif

u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr);

int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
                          struct fib_dump_filter *filter,
                          struct netlink_callback *cb);

int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nh,
                     u8 rt_family, unsigned char *flags, bool skip_oif);
int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nh,
                    int nh_weight, u8 rt_family, u32 nh_tclassid);
#endif  /* _NET_FIB_H */